Friday, November 07, 2008

Winter storm wallops southern MB

After some exceptionally nice weather to start the month, Mother Nature decided it was time to remind southern Manitobans that it's November in the Prairies. The first major winter storm of the season blasted southern MB Thursday and Thursday night with a variety of wintery weather, bringing snow, freezing rain, ice pellets, strong winds, as well as heavy rain to the area. In Winnipeg, the storm began with rain Thursday morning that changed to ice pellets driven by 50-70 km/h winds through the afternoon and evening. Ice pellets accumulated around 2-3 cm by evening along with some freezing rain. Overnight, precipitation changed to snow with 2-4 cm falling on top of the icy mess from the night before. In total, about 25-35 mm of melted precipitation fell over the Winnipeg area, with general snowfall accumulations of 5-8 cm across the city by Friday morning. Heavier amounts of snow were reported further west along the western Red River valley and MB escarpment, with 15-25 cm reported from the Pilot Mound area through Portage La Prairie. The snow and ice left many roads in poor driving conditions across the Red River Valley and SW MB, with travel not advised on several highways into Friday morning.

Further south and east of Winnipeg, precipitation was mostly rain Thursday, with significant amounts of 30-70 mm reported across portions of the southern Red River valley. Overall, an abrupt initiation to winter weather for residents of southern MB!


  1. Only a dusting of snow here in Steinbach. As one might say "no measurable accumulation". However the trees have a substantial layer of ice on them, similar to the storm back in late April. This leads me to believe that we never really had a chance at snow. The temperature dipped below freezing overnight, and obviously the result was freezing rain, not snow.

  2. Did anyone here about the reports of this storm down south!!!!
    41.5 inches of snow in Deadwood SD
    76 mph wind gust in Rapid City
    4 foot snow drifts.....

  3. Scott.. how lucky you are you don't have to contend with the messy slop we have here in Winnipeg.

    Now lets see how cold it gets... a high pressure ridge sitting over Nunavut will gradually build down and stall over us early next week. Looks pretty bad with low 850 mb temps and fresh snowpack.

    However, the snow pack is somewhat localized... well south of the contiguous snowline. There is no snow cover in Saskatchewan.. so westerly flow could take out a lot of the snow.

    Even better for us... there is bare ground in the RRV just south of here. So we may be able to escape the dreaded valley effect and actually warm up with a southerly flow.

    We'll see what happens end of next week as a disturbance tracks thru central Manitoba... it looks to drag some fairly warm air from the west ahead of it. Question is how much will surface with this localized snowfield.

  4. I'd love to see this snowpack disappear, but I have my doubts. This snowfall had a tremendous water content with it.. much of which is now frozen solid with several days of below freezing weather. We basically have a block of ice out there that will be difficult to melt away given the time of year and rapidly diminishing solar power. Unless our long wave pattern changes and we get a sustained spell of above normal temps with some rainfall, I'm afraid we're stuck with this snowcover the rest of the winter!

    By the way, this storm brought substantial precipitation (35-70 mm) to the already saturated Red River valley both here in MB and ND. Soil conditions are very wet going into the winter. Although spring flooding depends greatly on what kind of winter snowpack we get, this storm has likely elevated concerns about flooding of the Red next spring.

  5. Parts of West Winnipeg without power this morning due to all the freezing drizzle we had last night!

  6. What are the odds of lake-effect snow today? Winds are aligned down the lakes, and 850mb temperatures should be -10 to -12. I would assume the lake temperatures are still 2 or 3 degrees, so shouldn't we see some streamers?

  7. Wow it sure is gonna be a cold one out there tonight!
    -14 C will easily be obtained!
    -11 C already as of 9:00

  8. One more thing I would like to mention!
    I'm STUNNED how quickly cold temps. has set in this year.
    We were 18.8 C last week!!!
    NOW - 14 overnight lows!!!
    Rob you recall any other years where it was this harsh????
    Looking at the GFS looks like another storm on thursday with even colder set to follow!

  9. Looks like an Alberta Clipper will roll through on Thursday. Currently I would expect mostly 5 to 15cm, however some models are showing that 15 to 25cm is possible.

    Gusty North-West winds could create blizzard conditions on Thursday and/or Friday.

  10. Models have flip flopped a lot on this disturbance - initially taking it farther north. In the latest flip, the GFS moves it almost thru Winnipeg while GEMGlo now takes its south thru Fargo.

    Both models advertise relatively warm 850 temps at or slightly above 0 C over Winnipeg however. Consequently, freezing rain/ice pellets may come into play if surface temps get stuck below zero.

    This will be very interesting because all the bare ground over SE Manitoba and the red river basin in N Dakota will have a big impact on surface temps. I think we will be able to warm considerably with a SSE flow ahead of the disturbance.. temps in WC Minnesota are just above freezing already.

    The "rosy scenario" is one in which surface temps warm quickly.. we get enough warm air aloft .. and we get a nice rain that eats away this wretched heap of ice/snow we have. That is the optimist in me speaking of course.

    I think we will get at least some of the precip as freezing rain or ice pellets cutting down on potential snow accumulation. Still a lot of uncertainty with this system in terms of track and 850 MB/ surface temps. Rob, whats your take?

  11. Good points about the storm.

    I would agree that it will be hard to tell what the precipitation types will be for awhile yet. Unlike the previous storm, I think upper-air temperatures will be colder for the duration of the event. The models I have looked at don't put 850mb temperatures above the 0 to 2 degree range during the storm. The last storm had upwards of 4 degrees forecast at 850mb. They also show a small warm intrusion on the direct South side of the system, rather than the South-East side. I would expect a mostly snow event, however there will likely be both rain and freezing rain mixed in. With snow on the ground, and much colder temperatures all-around there shouldn't be as diverse and long-lived periods of freezing rain and ice pellets. Probably either rain, or snow, with a slight chance of freezing rain.

  12. Latest model runs are trending towards a more southern track on this clipper.. taking it through ND with the bulk of the pcpn falling as rain there before changing to snow on the backside Thursday night. There could be some snow in southern MB on the northern edge of the pcpn shield Thursday, but at this point, amounts look meager. Note however that our GLB model is hinting at potential for significant snowfall just south of us through ern ND/NW MN Thursday night into Friday along with strong northerly winds, so it still bears watching.

  13. The NAM and GFS completely agree on the amounts right now. They both are suggesting 10cm of snow. I am assuming that if the temperature is above 2C, then the snowfall probably wouldn't accumulate... Even if the 850mb temperature is below freezing...would that be correct?

    If snow would still accumulate above 2 degrees, the amounts would be more in the 10 to 15cm range.

  14. FYI: I just looked at the NWS's forecast for this storm, and they support the solution of having the storm slide right along the International border. Their QPF amounts show 5 to 15cm for most of Southern Manitoba. The NWS is going with a forecast consistent with the GFS.

  15. Looks like things could get very interesting tonight with several hours of freezing rain.
    We could be in for a very slow commute tomorrow morning~!

  16. Radar not looking terribly impressive at the moment for a significant freezing rain event tonight. Unless things develop quickly in the next hour or two, we'll likely get away with just some patchy brief freezing rain with this band tonight. Just as well.. we don't need any more ice out there!

  17. A mixed bag of precipitation coming in tonight with this next clipper system. Most areas of southern MB should see mainly rain as it moves through tonight... perhaps 2 to 5 mm. This may give the potential for pockets of freezing rain where surface temperatures are near or below freezing tonight. Further north and east of Winnipeg, pcpn may begin as wet snow in the southern Interlake and Whiteshell regions before changing over to rain.

    Otherwise temperatures are expected to stay at or above zero tonight, so there should be some melting of the ice and snow pack out there. Colder air returns by Thursday night and Friday in the wake of this system, with some light snow and increasing northwest winds.

  18. This system has really settled down in the models now. I agree completely with Rob on precipitation amounts tonight and Thursday. Maybe an additional 2 to 5cm of snow on Friday, as wrap-around precipitation comes into Southern Manitoba.

  19. We could see some heavy freezing rain tonight with this clipper. Most areas are just a shade above zero, in the 0.3 to 0.5C range. With all that moisture moving in, we could have an interesting situation on our hands later tonight.

  20. The CYWG TAF doesn't mention freezing precip so I'd be very surprised if there was any occurrence.

    TAF AMD CYWG 130217Z 1302/1324 18015G25KT 1/2SM FG VV001 TEMPO
    1302/1304 1SM BR OVC003
    FM130400 18015G25KT 1SM -RA BR OVC003 TEMPO 1304/1314 4SM -RA BR
    BECMG 1312/1314 27015KT
    FM131400 27015G25KT 4SM -RA BR OVC004 TEMPO 1314/1318 6SM -RA BR
    FM131800 29020G30KT 2SM -RASN OVC004 TEMPO 1318/1324 P6SM NSW
    RMK NXT FCST BY 130600Z=

  21. Well well.. precip changed over to heavy wet snow... so much for the nice rain. Instead now we will wake up to even bigger mess ..sheesh

  22. There were freezing rain warnings out for some parts of Southern Manitoba last night. Although I don't know if any accumulated, there certainly was a chance.

  23. I am guessing the intense forcing and lift associated with the band of warm advection precip last nite created enough 'dynamic cooling' for a change over to snow?

    Too bad we could not get farther above zero and melt more snow today ...barely 'breaking even' just by melting the slush that fell overnight. We were above zero for approx 40 consecutive hours, but never > 0.9 C I guess ...pretty pathetic.

    And for tomorrow... we tap that cold air lurking behind a secondary cold front. I am surprised EC did not mention dropping temps thru the day Friday for Winnipeg. Did not get a chance to look at the models - perhaps GEM is less aggressive with cold advection than GFS?

  24. Looks like some lake effect snow is now forming this morning!
    Maybe pick up a quick few centimeters with this band!!!